Developing renewable sources of feedstocks based on biomass for making distillate products, such as fuels or lubricants, is an area of ongoing interest. Use of biomass as a feedstock source is attractive from a perspective of avoiding depletion of mineral oil and gas sources. However, a variety of challenges remain in developing technologies for harvesting and processing feeds derived from biomass.
One potential source of biomass-derived feedstocks includes algae. Algae are an advantageous form of biomass in part because algae growth environments can be constructed, such as photobioreactors or artificially constructed ponds. Such photobioreactors and/or algae growth ponds can be placed in desirable locations, such as locations that do not compete with production of food for human consumption.
U.S. Pat. No. 5,958,761 describes a photobioreactor that includes a tubular housing surrounding an inner tubular growth environment. A fluid can be pumped through the tubular housing to provide control for the temperature in the photobioreactor.